It is not easy to remember the greatness of the issues which depend on scientific work, when that work is carried on, as it too often is, solely with the desire to gain a formal and definite answer to some question of petty detail. "That low man seeks a little thing to do, Sees it and does it: This high man, with a great thing to pursue, Dies ere he knows it. "That low man goes on adding one to one, His hundred's soon hit: This high man, aiming at a million, Misses a unit." INDEX. A Acids, connected by Lavoisier with oxygen, 91; Boyle's and other early definitions, 171; opposed in early medicine to alkalis, 172; grouped, 173; salts, 173; "the primordial acid," 174; oxygen not a necessary constituent, 184; new division of acids by Davy, 205; acids of different basicity, 237; modern conception of acids, 301. Affinity, chemical, apparently suspended by electricity, 191; history of term "affinity," 206; tables of, 207; dependent on electric states, 210. Air, composition of, determined by Cavendish, 79; Dalton's investigations, 116. Alchemy, 5; alchemical symbols of metals, 11; quotations from alchemists, 15, 17; alchemical poetry, 18. Alcoates, 235. Alkalis, 171; fixed and volatile, 173; mild and caustic, examined by Black, 176; connection with earths, 178; name of "base" given by Rouelle, 179; Gay-Lussac's alkalizing principle, 203. Ammonia, discovered by Priestley, 66. Atmolysis, 243. Atomic theory, dawn of, 117; early views of Greek philosophers, 123; of Epicurus and Lucretius, 124; of Newton and Bernoulli, 125; Dalton's new views--combination in simple multiples, 127, _et seq._; the theory made known by Dr. Thomson, 129; it is opposed at first by Davy, 130; Dalton's rules for arriving at atomic weights, 132; more accurately applied by Berzelius, 133, 162; diagrams of atoms, 118, 136; the theory as carried out by Gay-Lussac and Avogadro, 138, _et seq._; conception of the molecule, 140; molecular and atomic weight, 145; Graham's work on molecular reactions, 249; Berzelius's dualistic views, 212; they are attacked by Dumas, 260; conception of the compound radicle, 267; Laurent's unitary theory, 272; modern conception of molecule, 275; revision of atomic weights, 285; equivalency of atoms, 295. Avogadro, his elucidation of the atomic theory, 138, _et seq._; introduces the idea of molecules, 140; law known as Avogadro's law, 143. B Base (of salts), 179; basic lines in spectrum, 311. Becher, John J., born at Speyer, 26; his three principles of metals, 26; his principle of inflammability, 48; his views on acids, 174. Berthollet, analyzes ammonia, 66; adheres to the Lavoisierian theory of combustion, 95; questions doctrine of fixity of composition, 126; and necessary presence of oxygen in acids, 184; shows variable nature of affinities, 208.